Receive Paremeters on Multithreaded Server

I have created a multi-threaded server but can not figure out how to send an object/string. I think I have the ability to receive it already.

Server created:

vb Code:

serverThread = New Threading.Thread(AddressOf startHosting)

How do I specify an object or string parameter here?

vb Code:

connection.Connect(ip, port)

When new users connect my thread accepts an object parameter:

vb Code:

Private Sub clientWorker(ByVal param As Object)
End Sub

Quote:

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How do I specify an object or string parameter here?

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You don't. When you connect, all you do is connect. Once you're connected, then you can send data.

Ok, I had a feeling that was the case, so I re-wrote things to work around that.

My issue I have now is, how do I know what thread index/ip address data is arriving on?

This is my data arrival evenet

vb Code:

myNet.DataArrival

And this is the function that handles the data (yes, I know it is in C#)

C# Code:

private void winsock_DataArrival(string message)
{
}

I don't remember Sockets in VB.Net having a DataArrival event. They use Receive or BeginReceive to get data. Where did that event come from ?

It gets passed into the function from this event. Should this have more or different parameters?

vb Code:

Public Event DataArrival(ByVal message As String)

Quote:

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Originally Posted by rex64

It gets passed into the function from this event. Should this have more or different parameters?

vb Code:

Public Event DataArrival(ByVal message As String)

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What class is that event declared in ? The Socket class in the .Net framework has no such event.

Here is the stream watcher:

vb Code:

''' <summary>
    ''' Watches a stream while a user is connected? Stays alive while user is connected?
    ''' </summary>
    Private Sub streamWatcher(ByVal objStream As Object)
        Try
            Dim curStream As NetworkStream = CType(objStream, NetworkStream)
            Do Until Disposing = True Or curStream Is Nothing
 
                If curStream.DataAvailable Then
                    Dim message As String = receiveText(curStream)
                    RaiseEvent(DataArrival(message))
                End If
                Threading.Thread.Sleep(10)
 
            Loop
        Catch
        End Try
    End Sub

And he is called from here:

vb Code:

Dim t As New Threading.Thread(AddressOf streamWatcher)
t.Start(client.GetStream)
client = Nothing

You're using the TcpClient class....its documented in the MSDN. Read here. It will show you how to send data.

I looked at that, but we are doing multi-threaded and I am not sure how to check which client is communicating with the server. Sorry, I am a little new to multi-threaded networking.

You didn't define that DataArrival event properly....well at least according to the standard practice. Notice that all events in the framework have two parameters, a "sender As Object" parameter and and one based on an EventArgs object. This pattern ensures you can always get a reference to the object that raised the event through the "sender" parameter.

Ok. Can I raise the event like this:

vb Code:

RaiseEvent DataArrival(Me, message)

How can I keep track of which client index this belongs with? I have a ClientInfo list that I add clients to when they connect.

vb Code:

Public Structure ClientInfo
        Dim ip As System.Net.IPEndPoint
        Dim username As String
        Dim stream As NetworkStream
        Dim status As connectionStatusEnum
        Dim lastPing As DateTime
    End Structure
 
 Public clientList As New List(Of ClientInfo)
 
''' <summary>
    ''' Watches a stream while a user is connected? Stays alive while user is connected?
    ''' </summary>
    Private Sub streamWatcher(ByVal objStream As Object)
        Try
            Dim curStream As NetworkStream = CType(objStream, NetworkStream)
            Do Until Disposing = True Or curStream Is Nothing
 
                If curStream.DataAvailable Then
                    Dim message As String = receiveText(curStream)
                    RaiseEvent DataArrival(Me, message) 'I added 'me' here<<<<<<<<<<<
                End If
                Threading.Thread.Sleep(10)
 
            Loop
        Catch
        End Try
    End Sub

So let me get this straight, you want your streamWatcher sub to be able to identify which client receives data before raising DataArrival ? Is this correct ?

I just need to know which client or thread index the data is coming from. What do you recommend? I think I have multiple stream watchers. Maybe each one should pass in an index or a reference to the ClientInfo?

What is the class that contains that code you posted in post #12 ? What is its purpose ?

This is a networking class we have written to work with a 3D game we are creating.

Yes I understand but what does this class in particular do ? Could you post the code for the entire class ?

See attached

Attachment 93319

Impressive....did you write all that ? However I must complain that this class doesn't really seem to have a single purpose. It has stuff that seems to imply its some kind of server and yet also code that implies its a client. I really think you should separate these things. If you create a class to handle clients alone then it should come naturally to determine which client received or sent a message. What you have now are basically a collection of functions and I can see now why you're having trouble. Its a bad design. Sit back and really think about how you're designing these classes.

For example, I have a Client/Server application and every connection is represented by a kind of socket object I made. It raises events when it receives or sends data and I've no trouble determining who sent or received what because its all naturally encapsulated in a class instance.

[EDIT]

Hmm...looking more at your code it seems that you did indeed create this class as a client....Can you clear this up ? Does the clsNetEasy class represent a client connection or is it just a collection of network functions ?

Also, take a look at this post where I have attached a project that simulates multiple devices being pinged. It should serve to adequately demonstrate how to identify which device is doing the communication at any given time and also how to multi-thread it properly.

It looks like you are creating a different instance of the class for each thread to keep track of them. Is that what you recommend I do? It sounds like it would use more resources, but it should work better. Let me know your thoughts, and if I figured out the puzzle :)

It looks like I am creating the threads on the fly, and not managing them very well. Should I have a list of threads? Or a list of classes with a single thread in each one? Or what is the best?

Quote:

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Originally Posted by rex64

It looks like you are creating a different instance of the class for each thread to keep track of them. Is that what you recommend I do?

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Not only do I recommend it...I strongly recommend it.

Quote:

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Originally Posted by rex64

...It sounds like it would use more resources...

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Well we are not in the DOS era anymore where you only had 640KB of memory to play with. You can go hog wild in this case. Its more than worth it.

Quote:

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Originally Posted by rex64

It looks like I am creating the threads on the fly, and not managing them very well. Should I have a list of threads? Or a list of classes with a single thread in each one? Or what is the best?

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You should have a list of objects and each of these objects can manage their own threads internally. You shouldn't have to interact with these threads outside of the object. Interact with the object's methods, properties and events.

Ok, so this is what I am planning:
clsNetClient (connects to the server)
clsNetServer (has list of clsNetServerConnection)
clsNetServerConnection (each connection will be its own class)

Quote:

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Originally Posted by Niya

You should have a list of objects and each of these objects can manage their own threads internally. You shouldn't have to interact with these threads outside of the object. Interact with the object's methods, properties and events.

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Here is my plan. Let me know your thoughts.

Attachment 93425

Should I have one total or 1 per client of these:

vb Code:

Dim server As TcpListener = Nothing

And what about this?

vb Code:

Dim connection As TcpClient = Nothing

Quote:

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Originally Posted by rex64

Here is my plan. Let me know your thoughts.

Attachment 93425

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Yes this is a very good design. Its exactly what I had in mind.

Quote:

---

Originally Posted by rex64

Should I have one total or 1 per client of these:

vb Code:

Dim server As TcpListener = Nothing

And what about this?

vb Code:

Dim connection As TcpClient = Nothing

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Well clients don't need to listen do they ;)

Should each client connection on the server have its own TcpListner?
Dim server As TcpListener = Nothing

So if 100 clients were connected I would have:
QTY1: clsNetServer
QTY100: clsNetConnection

And on the Client's computer, each would have their own clsNetClient.

Quote:

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Originally Posted by rex64

Should each client connection on the server have its own TcpListner?

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What is a TcpListener for ?

I think TcpListener is for watching an ip address and port. So I am thinking I should only need 1 of these. Are the clients just network streams? To disconnect a client do you just dispose of the stream?

vb Code:

''' <summary>
    ''' Starts hosting...
    ''' </summary>
    Public Sub hostServer(ByVal username As String, ByVal ServerString As String)
        If myIpInfo.Count > 0 Then
            server = New TcpListener(IPAddress.Parse(myIpInfo(0).IPAddress), serverPort) '1244
 
            server.Start()
        End If
        _ServerString = ServerString
 
        serverThread = New Threading.Thread(AddressOf startHosting)
        serverThread.Start(username)
 
    End Sub

A server's job is to listen for client connections, not just in this scenario but in any scenario where there is a server/client paradigm. In this case I'm assuming you are opting to encase a TcpListener within a larger server class. The TcpListener has an AcceptTcpClient method which returns a TcpClient object when a client attempts to make a connection. The TcpClient object represents the connection between the specific client machine and the server So just think of it, you have one server machine that can accept incoming connections from multiple client machines, each client having its own stream. If you have a client class that wraps a TcpClient object inside then you wouldn't need a TcpListener. A server listens not a client.

If you want to close a connection then you do so through the TcpClient class which has a Close method. All your communication would be through a TcpClient object on both ends. The TcpListener is only responsible for creating TcpClient objects for communication between client and server.

You questioning gives me an instinctive feeling that you don't fully understand the Client/Server paradigm. I suggest you read this to wrap your head around it.

Thanks. I do understand the client server, but I am trying to learn the best way to implement it in VB .NET. So if I understand this correctly:
clsNetServer would have a single TcpListener. When a client connect to the server the TcpListener would automatically create a TcpClient object which I could then pass to the constructor of ClsNetConnection. Does that sound about correct? I would not need a stream because the TcpClient contains a stream. Hope you enjoyed Thanksgiving!

Quote:

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Originally Posted by rex64

Thanks. I do understand the client server, but I am trying to learn the best way to implement it in VB .NET. So if I understand this correctly:
clsNetServer would have a single TcpListener. When a client connect to the server the TcpListener would automatically create a TcpClient object which I could then pass to the constructor of ClsNetConnection. Does that sound about correct? I would not need a stream because the TcpClient contains a stream.

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Ya...you got the idea. The TcpClient however is not really created automatically, not by the TcpListener anyway. A call to AcceptTcpClient blocks until a client establishes a connection. Only then it returns a TcpClient.

Quote:

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Originally Posted by rex64

Hope you enjoyed Thanksgiving!

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Well we don't celebrate thanks giving but thank you all the same :)

Things are working better, but for some reason I think the stream may be getting damaged. I can send data to the server and it receives it but I am not getting any data back on the stream after I run a few commands. It goes to the sendData inside the else statement, but the client (on the same computer) does not receive the chat messages. Other things seem to arrive ok. We have been having weird problems like this for a while. It seems like if we comment certain things out that it works, but we have not figured out why. Right now I do not see any reason it should not be working at this point.

What tests do you recommend on the stream?

vb Code:

''' <summary>
    ''' Sends text on the stream to the server.
    ''' </summary>
    Public Sub sendText(ByVal message As String)
 
        If stream Is Nothing Then
            If connection IsNot Nothing Then
                If connection.Connected Then
                    sendData(System.Text.Encoding.ASCII.GetBytes(message), connection.GetStream)
                End If
            End If
        Else
            sendData(System.Text.Encoding.ASCII.GetBytes(message), stream)
        End If
    End Sub

Also, it looks like this stream loop is not active all the time. Should this loop be running the entire time that it is connected? Or should this close at some point? Is this a good way to do it?

vb Code:

''' <summary>
    ''' Watches a stream while a user is connected? Stays alive while user is connected?
    ''' </summary>
    Private Sub streamWatcher(ByVal objStream As Object)
        Try
            Dim curStream As NetworkStream = CType(objStream, NetworkStream)
            Do Until Disposing = True Or curStream Is Nothing  
 
                If curStream.DataAvailable Then
                    Dim message As String = receiveText(curStream)
                    RaiseEvent DataArrival(Me, message)
                End If
                Threading.Thread.Sleep(10)
 
            Loop
        Catch
        End Try
    End Sub

The loop should be running the entire time on another thread. It should exit on a disconnect. This is what I do for my network applications.

Ok, I think I am understanding everything. The loop is getting stuck in startHosting. Disposing is = to true in the debugger, but it does not seem to get off that line of code. It has a green arrow and when I press F8 (step into) or Start it acts like it is playing (which is weird for F8 (Step Into)). Then when I press pause it is right back on that exact same line of code.

I may be crazy, but looking at this code closer, during normal running, isn't this stuck in an infinite loop of creating threads? This sounds very bad :)

It is getting stuck on this line:
client = server.AcceptTcpClient()

In here:

vb Code:

''' <summary>
    ''' Used by host server.
    ''' </summary>
    Private Sub startHosting(ByVal username As Object)
        Dim client As TcpClient
 
        _username = CType(username, String)
 
        'before anyone tries changing this, it MUST BE AN OBJECT ARRAY!!!!
        'it stores a TCPClient and a string, so explicit typing WON'T work. -Ray
 
        Do Until _close Or Disposing = True
            Try
                client = server.AcceptTcpClient()
 
 
 
                Dim myThread As New Threading.Thread(AddressOf clientWorker)
                myThread.Start(client)
            Catch
                _close = True
            End Try
 
        Loop
    End Sub

client = server.AcceptTcpClient() is a blocking call. I expect it would only proceed after receiving a connection in which case the loop would proceed and eventually reach right back there. startHosting should be running on another thread so as to prevent locking up the UI.